/*
    Copyright (C) 2020 Alex Lewontin

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

/**
 * @file    hal_usb_lld.h
 * @brief   NUC123 USB subsystem low level driver header.
 *
 * @addtogroup USB
 * @{
 */

#ifndef HAL_USB_LLD_H
#define HAL_USB_LLD_H

#if HAL_USE_USB || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver constants.                                                         */
/*===========================================================================*/

/**
 * @brief   Maximum endpoint address.
 * @details This value does not include the endpoint 0 which is always present.
*/
#define USB_MAX_ENDPOINTS 2

/**
 * @brief   Status stage handling method.
 */
#define USB_EP0_STATUS_STAGE USB_EP0_STATUS_STAGE_SW

/**
 * @brief   The address can be changed immediately upon packet reception.
 */
#define USB_SET_ADDRESS_MODE USB_LATE_SET_ADDRESS

/**
 * @brief   Method for set address acknowledge.
 */
#define USB_SET_ADDRESS_ACK_HANDLING USB_SET_ADDRESS_ACK_SW

/**
 * @brief   Speed of the USB hardware's input clock. This must be 48 MHz.
 */
#define NUC123_USBD_CLK 48000000UL

/*===========================================================================*/
/* Driver pre-compile time settings.                                         */
/*===========================================================================*/

/**
 * @name    NUC123 configuration options
 * @{
 */
/**
 * @brief   USB driver enable switch.
 * @details If set to @p TRUE the support for USB1 is included.
 * @note    The default is @p TRUE.
 */
#if !defined(NUC123_USB_USE_USB1) || defined(__DOXYGEN__)
#define NUC123_USB_USE_USB1 TRUE
#endif

/**
 * @brief   USB1 interrupt priority level setting.
 */
#if !defined(NUC123_USB_IRQ_PRIORITY) || defined(__DOXYGEN__)
#define NUC123_USB_IRQ_PRIORITY 3
#endif
/** @} */

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

#if NUC123_PLLCLK < NUC123_USBD_CLK
#error "NUC123_PLLCLK must be at least 48 MHz for USB"
#endif

#define NUC123_USBD_CLKDIV ((NUC123_PLLCLK) / (NUC123_USBD_CLK))

#if ((NUC123_USBD_CLKDIV * NUC123_USBD_CLK) != NUC123_PLLCLK) ||            \
    (16 < NUC123_USBD_CLKDIV)
#error "Cannot generate required 48MHz from the configured PLL frequency"
#endif

#if !defined(NUC123_USB_USE_USB1) || (!NUC123_USB_USE_USB1)
#error "NUC123 USB subsystem enabled, but no driver configured"
#endif

/*===========================================================================*/
/* Driver data structures and types.                                         */
/*===========================================================================*/

/**
 * @brief   Type of an IN endpoint state structure.
 */
typedef struct {
  /**
   * @brief   Requested transmit transfer size.
   */
  size_t txsize;
  /**
   * @brief   Transmitted bytes so far.
   */
  size_t txcnt;
  /**
   * @brief   Pointer to the transmission linear buffer.
   */
  const uint8_t *txbuf;
#if USB_USE_WAIT || defined(__DOXYGEN__)
  /**
   * @brief   Waiting thread.
   */
  thread_reference_t thread;
#endif
  /* End of the mandatory fields.*/
} USBInEndpointState;

/**
 * @brief   Type of an OUT endpoint state structure.
 */
typedef struct {
  /**
   * @brief   Requested receive transfer size.
   */
  size_t rxsize;
  /**
   * @brief   Received bytes so far.
   */
  size_t rxcnt;
  /**
   * @brief   Pointer to the receive linear buffer.
   */
  uint8_t *rxbuf;
#if USB_USE_WAIT || defined(__DOXYGEN__)
  /**
   * @brief   Waiting thread.
   */
  thread_reference_t thread;
#endif
  /* End of the mandatory fields.*/
} USBOutEndpointState;

/**
 * @brief   Type of an USB endpoint configuration structure.
 * @note    Platform specific restrictions may apply to endpoints.
 */
typedef struct {
  /**
   * @brief   Type and mode of the endpoint.
   */
  uint32_t ep_mode;
  /**
   * @brief   Setup packet notification callback.
   * @details This callback is invoked when a setup packet has been
   *          received.
   * @post    The application must immediately call @p usbReadPacket() in
   *          order to access the received packet.
   * @note    This field is only valid for @p USB_EP_MODE_TYPE_CTRL
   *          endpoints, it should be set to @p NULL for other endpoint
   *          types.
   */
  usbepcallback_t setup_cb;
  /**
   * @brief   IN endpoint notification callback.
   * @details This field must be set to @p NULL if the IN endpoint is not
   *          used.
   */
  usbepcallback_t in_cb;
  /**
   * @brief   OUT endpoint notification callback.
   * @details This field must be set to @p NULL if the OUT endpoint is not
   *          used.
   */
  usbepcallback_t out_cb;
  /**
   * @brief   IN endpoint maximum packet size.
   * @details This field must be set to zero if the IN endpoint is not
   *          used.
   */
  uint16_t in_maxsize;
  /**
   * @brief   OUT endpoint maximum packet size.
   * @details This field must be set to zero if the OUT endpoint is not
   *          used.
   */
  uint16_t out_maxsize;
  /**
   * @brief   @p USBEndpointState associated to the IN endpoint.
   * @details This structure maintains the state of the IN endpoint.
   */
  USBInEndpointState *in_state;
  /**
   * @brief   @p USBEndpointState associated to the OUT endpoint.
   * @details This structure maintains the state of the OUT endpoint.
   */
  USBOutEndpointState *out_state;
  /* End of the mandatory fields.*/

  /**
   * @brief   Reserved field, not currently used.
   * @note    Initialize this field to 1 in order to be forward compatible.
   */
  uint16_t                      ep_buffers;
  /**
   * @brief   Pointer to a buffer for setup packets, not currently used.
   * @details Setup packets require a dedicated 8-bytes buffer, set this
   *          field to @p NULL for non-control endpoints.
   */
  uint8_t                       *setup_buf;
} USBEndpointConfig;

/**
 * @brief   Type of an USB driver configuration structure.
 */
typedef struct {
  /**
   * @brief   USB events callback.
   * @details This callback is invoked when an USB driver event is registered.
   */
  usbeventcb_t event_cb;
  /**
   * @brief   Device GET_DESCRIPTOR request callback.
   * @note    This callback is mandatory and cannot be set to @p NULL.
   */
  usbgetdescriptor_t get_descriptor_cb;
  /**
   * @brief   Requests hook callback.
   * @details This hook allows to be notified of standard requests or to
   *          handle non standard requests.
   */
  usbreqhandler_t requests_hook_cb;
  /**
   * @brief   Start Of Frame callback.
   */
  usbcallback_t sof_cb;
  /* End of the mandatory fields.*/
} USBConfig;

/**
 * @brief   Structure representing an USB driver.
 */
struct USBDriver {
  /**
   * @brief   Driver state.
   */
  usbstate_t state;
  /**
   * @brief   Current configuration data.
   */
  const USBConfig *config;
  /**
   * @brief   Bit map of the transmitting IN endpoints.
   */
  uint16_t transmitting;
  /**
   * @brief   Bit map of the receiving OUT endpoints.
   */
  uint16_t receiving;
  /**
   * @brief   Active endpoints configurations.
   */
  const USBEndpointConfig *epc[USB_MAX_ENDPOINTS + 1];
  /**
   * @brief   Fields available to user, it can be used to associate an
   *          application-defined handler to an IN endpoint.
   * @note    The base index is one, the endpoint zero does not have a
   *          reserved element in this array.
   */
  void *in_params[USB_MAX_ENDPOINTS];
  /**
   * @brief   Fields available to user, it can be used to associate an
   *          application-defined handler to an OUT endpoint.
   * @note    The base index is one, the endpoint zero does not have a
   *          reserved element in this array.
   */
  void *out_params[USB_MAX_ENDPOINTS];
  /**
   * @brief   Endpoint 0 state.
   */
  usbep0state_t ep0state;
  /**
   * @brief   Next position in the buffer to be transferred through endpoint 0.
   */
  uint8_t *ep0next;
  /**
   * @brief   Number of bytes yet to be transferred through endpoint 0.
   */
  size_t ep0n;
  /**
   * @brief   Endpoint 0 end transaction callback.
   */
  usbcallback_t ep0endcb;
  /**
   * @brief   Setup packet buffer.
   */
  uint8_t setup[8];
  /**
   * @brief   Current USB device status.
   */
  uint16_t status;
  /**
   * @brief   Assigned USB address.
   */
  uint8_t address;
  /**
   * @brief   Current USB device configuration.
   */
  uint8_t configuration;
  /**
   * @brief   State of the driver when a suspend happened.
   */
  usbstate_t saved_state;
#if defined(USB_DRIVER_EXT_FIELDS)
  USB_DRIVER_EXT_FIELDS
#endif
  /* End of the mandatory fields.*/
};

/*===========================================================================*/
/* Driver macros.                                                            */
/*===========================================================================*/

/**
 * @brief   Returns the current frame number.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @return              The current frame number.
 *
 * @notapi
 */
#define usb_lld_get_frame_number(usbp) 0

/**
 * @brief   Returns the exact size of a receive transaction.
 * @details The received size can be different from the size specified in
 *          @p usbStartReceiveI() because the last packet could have a size
 *          different from the expected one.
 * @pre     The OUT endpoint must have been configured in transaction mode
 *          in order to use this function.
 *
 * @param[in] usbp      pointer to the @p USBDriver object
 * @param[in] ep        endpoint number
 * @return              Received data size.
 *
 * @notapi
 */
#define usb_lld_get_transaction_size(usbp, ep)                              \
  ((usbp)->epc[ep]->out_state->rxcnt)

/**
 * @brief   Connects the USB device.
 *
 * @api
 */
#define usb_lld_connect_bus(usbp)                                           \
  do {                                                                      \
    USBD->DRVSE0 = (0 << USBD_DRVSE0_DRVSE0_Pos);                           \
  } while (0)

/**
 * @brief   Disconnect the USB device.
 *
 * @api
 */
#define usb_lld_disconnect_bus(usbp)                                        \
  do {                                                                      \
    USBD->DRVSE0 = (1 << USBD_DRVSE0_DRVSE0_Pos);                           \
  } while (0)

/**
 * @brief   Start of host wake-up procedure.
 *
 * @notapi
 */
#define usb_lld_wakeup_host(usbp)                                           \
  do {                                                                      \
    USBD->ATTR |= USBD_ATTR_RWAKEUP_Msk;                                    \
    osalThreadSleepMilliseconds(10);                                        \
    USBD->ATTR &= ~USBD_ATTR_RWAKEUP_Msk;                                   \
    _usb_wakeup(&USBD1);                                                    \
  } while (0)

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#if NUC123_USB_USE_USB1 && !defined(__DOXYGEN__)
extern USBDriver USBD1;
#endif

#ifdef __cplusplus
extern "C" {
#endif
void          usb_lld_init(void);
void          usb_lld_start(USBDriver *usbp);
void          usb_lld_stop(USBDriver *usbp);
void          usb_lld_reset(USBDriver *usbp);
void          usb_lld_set_address(USBDriver *usbp);
void          usb_lld_init_endpoint(USBDriver *usbp, usbep_t ep);
void          usb_lld_disable_endpoints(USBDriver *usbp);
usbepstatus_t usb_lld_get_status_in(USBDriver *usbp, usbep_t ep);
usbepstatus_t usb_lld_get_status_out(USBDriver *usbp, usbep_t ep);
void          usb_lld_read_setup(USBDriver *usbp, usbep_t ep, uint8_t *buf);
void          usb_lld_start_out(USBDriver *usbp, usbep_t ep);
void          usb_lld_start_in(USBDriver *usbp, usbep_t ep);
void          usb_lld_stall_out(USBDriver *usbp, usbep_t ep);
void          usb_lld_stall_in(USBDriver *usbp, usbep_t ep);
void          usb_lld_clear_out(USBDriver *usbp, usbep_t ep);
void          usb_lld_clear_in(USBDriver *usbp, usbep_t ep);
#ifdef __cplusplus
}
#endif

#endif /* HAL_USE_USB */

#endif /* HAL_USB_LLD_H */

/** @} */
